Just about any good ionic or colloidal silver product would be fine. The top two colloidal products are Mesosilver and Advanced Colloidal Silver and both should work wonderfully. I would opt for Advanced Colloidal Silver because it has a bit higher ionic content (about 15% versus about 5% for Mesosilver). Actually, an even better option for nebulizing might be Advanced Ionic Silver, which is mostly ionic silver with very small particle sizes. Unlike situations where you need to get the silver into your bloodstream, nebulizing is much the same as topical use and ionic works great for topical and/or direct contact situations. For that matter, home made mostly ionic silver would probably work good too.
Pay no attention to what the other poster is saying - he is full of misunformation about chemicals, hair loss, other products, etc. His lack of knowledge is plain to see when he says that another colloidal silver product costs $2.45 per particle (still hasn't figured out what PPM means or the difference between PPM and particles). He also fails to recognize that other products have been measured to have particles sizes ranging down to a mere 0.65 nm or less (as opposed to his claim of hundreds of nanometer particle sizes). He obviously is here to hype his products and won't let the truth get in the way of his sales pitch.